check-stylish-haskell.yml

name: Check Stylish Haskell

on:
  merge_group:
  pull_request:

# When pushing branches (and/or updating PRs), we do want to cancel previous
# build runs. We assume they are stale now; and do not want to spend CI time and
# resources on continuing to continue those runs. This is what the concurrency.group
# value lets us express. When using merge queues, we now have to consider
# - runs triggers by commits per pull-request
#   we want to cancel any previous run. So they should all get the same group (per PR)
# - runs refs/heads/gh-readonly-queue/<target branch name> (they should all get their
#   unique git ref, we don't want to cancel any of the ones in the queue)
# - if it's neither, we fall back to the run_id (this is a unique number for each
#   workflow run; it does not change if you "rerun" a job)
concurrency:
  group: ${{ github.workflow }}-${{ github.event.type }}-${{ startsWith(github.ref, 'refs/heads/gh-readonly-queue/') && github.ref || github.event.pull_request.number || github.run_id }}
  cancel-in-progress: true

jobs:
  check-stylish-haskell:
    runs-on: ubuntu-latest

    strategy:
      fail-fast: false

    env:
      # Modify this value to "invalidate" the cabal cache.
      CABAL_CACHE_VERSION: "2023-07-12"

      STYLISH_HASKELL_VERSION: "0.14.4.0"

      STYLISH_HASKELL_PATHS: >
        cardano-api

    steps:
    - name: Download stylish-haskell
      run: |
        version="${{ env.STYLISH_HASKELL_VERSION }}"

        curl -sL \
          "https://github.com/haskell/stylish-haskell/releases/download/v$version/stylish-haskell-v$version-linux-x86_64.tar.gz" \
          | tar -C "/tmp" -xz

        echo "PATH=/tmp/stylish-haskell-v$version-linux-x86_64:$PATH" >> "$GITHUB_ENV"

    - uses: actions/checkout@v3

    - name: Run stylish-haskell over all Haskell files (always succeeds)
      run: |
        git add .
        git stash

        for x in $(git ls-tree --full-tree --name-only -r HEAD ${{ env.STYLISH_HASKELL_PATHS }}); do
          if [ "${x##*.}" == "hs" ]; then
            if grep -qE '^#' "$x"; then
              echo "$x contains CPP.  Skipping."
            else
              stylish-haskell -i "$x"
            fi
          fi
        done

        git --no-pager diff

    - name: Run stylish-haskell over all modified files
      run: |
        git add .
        git stash
        git fetch origin ${{ github.base_ref }} --unshallow
        for x in $(git diff --name-only --diff-filter=ACMR origin/${{ github.base_ref }}..HEAD ${{ env.STYLISH_HASKELL_PATHS }}); do
          if [ "${x##*.}" == "hs" ]; then
            if grep -qE '^#' "$x"; then
              echo "$x contains CPP.  Skipping."
            else
              stylish-haskell -i "$x"
            fi
          fi
        done

        git --no-pager diff --exit-code